Flanked by government officials, he accurately told the nation that the risk to Americans remains low, that the country should prepare out of an abundance of caution and that a vaccine was in the works.

"The risk to the American people remains very low," Trump said during the news conference.

Later, pressed on whether he agreed with health officials' view that coronavirus will inevitably spread in the U.S., he said: "I don't think it's inevitable. It probably will. It possibly will. It could be at a very small level, or it could be at a larger level. Whatever happens, we're totally prepared."

"It's not so much a question of if this will happen anymore but rather more a question of exactly when this will happen and how many people in this country will have severe illness," Dr. Nancy Messonnier, the head of the National Center for Immunization and Respiratory Diseases at the Centers for Disease Control and Prevention, said during a media briefing Tuesday.

"We're rapidly developing a vaccine," Trump said. "The vaccine is coming along well, and in speaking to the doctors we think this is something that we can develop fairly rapidly."

Later, he added: "But that's a little bit like the flu. It's a little like the regular flu that we have flu shots for. And we'll essentially have a flu shot for this in a fairly quick manner."

This is a bit exaggerated. Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said in the same news conference that a potential vaccine is in rapid development but that a final product is at least a year to 18 months away — if trials that are happening now succeed. This is fast for a vaccine, but it's not going to help anyone imminently.

The president repeatedly pointed to the 15 cases of coronavirus in the U.S.

There are actually 60 in total, but the CDC categorizes them in two groups. Fifteen were diagnosed in the U.S. — Trump said he calls them "the original 15" — and 45 cases involve people who were repatriated with the virus from abroad.

"I want you to understand something that shocked me when I saw it, that I spoke with Dr. Fauci on this, and I was really amazed, and I think most people were amazed to hear it. The flu in our country kills from 25,000 people to 69,000 people a year. That was shocking to me," Trump said before comparing it to those sickened by the coronavirus. "And so far, if you look at what we have with the 15 people, and they're recovering, one is pretty sick but hopefully will recover. But the others are in great shape."

So far, it's true that the flu kills a lot more people. Coronavirus is a respiratory virus like flu, and the symptoms are similar, like fever, cough and fatigue. But comparing flu and coronavirus is difficult, because flu has a predictable season and there are still so many unknowns about coronavirus.